There are different processes used to stress bacterial metabolism in activated sludge tanks to favour catabolic reaction with respect to anabolic ones. A well known process is Cannibal by Siemens.
I would be glad to know any full scale example of such process and any news from research activities.
Walter,
Contact Queensland Urban Utilities for details about the thermal hydrolysis system using the Cambi Processes which conditions dewatered waste activated sludge prior to anaerobic digestion at the Oxley Creek wastewater treatment plant.
urbanutilities.com.au
One approach to minimize the sludge production in AS processes involves the reduction of substrate utilization rate (SUR) and food to microorganisms ratio (F/M). This can be achieved by amplifying microbial cell lysis and generating biomass growth from the lysis products, being defined as cryptic growth (Rocher et al., 1999). Minimizing sludge production in aerobic wastewater treatment plants (WWTPs) through bacterial ecosystem manipulation is well known. Metabolic changes and predating bacteria growth, occurring at high solids retention time (SRT) and deferent regimes (extended aeration, cyclic alteration between anaerobic anoxic and oxic conditions etc.), result in low observed sludge yields in a biological process (Lee and Welander, 1996; Loosdrecht and Henze, 1999; Foladori et al., 2010).
According to recent reviews, mechanisms for reducing sludge production in WWTPs are extended aeration, alternating anaerobic/anoxic/oxic regimes, advanced oxidation, enhanced endogenous decay, metabolic uncouplers, selective bacterial growth (predator species) mechanical and ultrasonic disintegration, thermal treatment and operating parameters such as SRT, dissolved oxygen concentration (DO), temperature, sludge recycle ratio (Canales et al., 1994; Rocher et al., 1999; Mahmood and Elliott, 2006; Foladori et al., 2010; Yang et al., 2011; Guo et al., 2013; Semblante et al., 2014). Increased oxygen concentration in activated sludge flocs contributes to excess sludge minimization (Abbassi et al., 1999). Experimental results have shown that reduction of excess sludge production can be achieved by raising dissolved oxygen concentration in the mixed liquor. The increased oxygen concentration in the mixed liquor leads to a deep diffusion of oxygen, which subsequently enlarges the aerobic volume inside the resulting flocs and the oxygenated microorganisms in the floc matrix are degraded (Abbassi et al., 1999).
PS. This manuscript may also help you:
http://www.pubfacts.com/detail/25463928/Evaluating-sedimentation-problems-in-activated-sludge-treatment-plants-operating-at-complete-sludge-
Dear Mr Malacrida,
see if you have access for this article:
http://www.sciencedirect.com/science/article/pii/S096085241500139X
I think it will help you.
Best Regards
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology
- Microorganisms
- Bacteria